There exists a plurality of situations wherein it is desirable to control accidental fluid backflow flow in specific circumstances, or to monitor the fluid flow in pipes.
In a building or other structures serviced via an underground sewer line, it sometimes occurs that the main sewer line or the branch line leading from the building to the main sewer line becomes clogged. Indeed, the problem of basement flooding from sewer line water backflow flow has become prevalent in recent years. The backflow may be caused by a variety of problems including when the flow capacity of the sewer system is exceeded by the rain water inflow rate into the system.
The risk of water backflow is present in most storm sewer systems where the storm sewers are rarely of a sufficient size to accommodate unusually heavy rain storms. This risk is sometimes present in sanitary sewer system where there is a water leakage into the sewer system through manholes, cracks in sewer line joints or where improper roof down spout connections are made to the system which normally should carry only the water and sewage draining from sinks, toilets, washing machines drain lines and basement floor drains.
Clogging of the sewer line may be caused by many factors including broken or misaligned pipes. Such broken or misaligned pipes present projections, ridges or sharp bends on which bulk material hangs up and causes a nucleus fore clogging. Other times, roots from surface plants invade the pipe in search of moisture which may be leaking from poorly formed joints in the pipe and these roots also can form the nucleus of the clog in the pipe. Whatever the cause of the clog, the effect is that the sewage becomes backed up in the line and eventually the backflow will overflow from the fixtures and drains in the building.
Modern sewer systems are equipped with clean out pipes or outlets. The clean out is accomplished by inserting a Tee or Y joint in the sewer line just outside the building or in the basement. Leading from the Tee or Y joint is a vertical or near vertical clean out pipe which is kept or plugged near the ground surface. While this type of clean out allows for access to the sewer line for removal of clog, it does not prevent the backflow or sewage through the sewer line which will eventually overflow from the fixtures or drain inside of the building.
Backflow problems in sanitary sewer lines leading to an individual home can be substantially eliminated by the application of a backflow preventing valve in the pipe line extending between the home and the underground sanitary sewer line running along the street involved. When backflow water pressure builds up, the backflow preventing valve is closed or closes to prevent the water in sanitary sewer lines from backing up into the user's home.
However, many home owners simply do not wish to install such systems. Indeed, conventional flow protection usually consists of a simple check valve, more particularly a flap valve mounted inside the sewer duct, which functions as a pivotable gate providing for unidirectional flow of the fluid in the sewer line away from the source. However, these pivotal gates are only efficient when the fluid flow inside the sewer is at fast speed, since the gate will then be forcibly pivotally biased against its annular seat inside the sewer duct by the hydrodynamic forces. Such pivotal gate valve systems are however ineffective in conditions of sewer duct clogging, since the fluid level inside the sewer duct raises quite progressively, and the fluid flow speed is usually small, which would not provide a hydrodynamic force suitable for pivotally biasing the pivotal gate against its annular seat in a fluid tight fashion.
Inflatable bladders may be used in place of pivotal gate valves, although these bladders create a phenomenon of fluid flow turbulence. When these bladders are in their inoperative deflated condition, they remain in a radially inwardly projecting condition inside the sewer duct passage that constitutes a partially obstructive element. Moreover, such inflatable bladders may require manual handling to be deflated.
Furthermore, most conventional fluid backflow mitigating prior art systems are not efficient in early detection of fluid and thus are relatively unreliable and inefficient.